Evolution of end-of-range defects in Si after Xe implantation studied by grazing incidence diffuse X-ray scattering

Abstract

We demonstrate that grazing incidence diffuse X-ray scattering (GI-DXS) is well suited to investigate the temporal evolution of EOR defects during rapid thermal annealing (RTA) at 1173 K (900 °C) in Si (001) after pre-amorphisation by Xe ions. From a detailed analysis of the DXS intensity close to 220 in reciprocal space, two scattering components are identified. One component is attributed to free, excess Si interstitials. The other component is manifested by streaks along the <111> directions, which are typical for faulted dislocation loops (FDLs). The size and number of FDLs was determined with high statistical accuracy as a function of the annealing time between 5 and 80 s. We give evidence that the total number of excess Si interstitials is constant in the EOR defects region, either in the form of point-like defects or bonded to FDLs. The influence of the sample surface as a sink for Si interstitials can be excluded. For annealing times shorter than 20 s, the population of point-like defects diminishes considerably while the number of relatively small FDLs (20–24 nm diameter) increases. For longer annealing times the main process is the size increase of the FDLs up to 34 nm by Ostwald ripening, while their number stays almost constant, still bonding Si interstitials from the available excess Si atoms. The growth of the FDLs is found to be diffusion-limited. We emphasize that DXS is a non-destructive method to investigate point defects and extended defects in the EOR region simultaneously, so that the dynamic exchange between them can be studied.